U.S. stocks rallied yesterday largely on a belief among investors that the Federal Reserve will take further action to stimulate the economy. The Fed concludes a two-day meeting around noon today. Afterwards, Chairman Ben Bernanke will hold a news conference to explain the Fed's strategy.

As NPR's John Ydstie reports, there are several things the Fed could do to try to boost growth, but whether they'd be effective is debatable.

JOHN YDSTIE, BYLINE: Michael Feroli, chief U.S. economist at JPMorgan Chase expects the Fed to take some action, but he says...

MICHAEL FEROLI: It's not going to be a game changer.

YDSTIE: Most likely, Feroli says, the Fed will extend the program investors have dubbed Operation Twist. Right now, it's scheduled to expire June 30th.

Operation Twist works like this: The Fed sells short-term securities it holds -those that mature in less than three years. Then it takes the money and buys longer term securities like 30-year Treasury bonds. The goal is to push down long-term interest rates for businesses and households, including mortgage rates. But partly because so many Americans have damaged credit scores and can't qualify for refinancing or new mortgages, there's some question about how effective the program has been.

Feroli thinks it may have contributed to lowering rates about a 10th of a percent.

FEROLI: So nothing that's really going to turn things around in a quick manner, but hopefully, you know, just leaning on things to push them a little more in the right direction.

YDSTIE: Feroli says he also thinks Fed policymakers will change their guidance and say it's likely interest rates will remain very low into 2015. They previously said until late 2014.

Feroli doesn't think policymakers will announce a third round of quantitative easing, in which the Fed adds even more money to the economy by purchasing additional bonds. He says that might raise criticism from inflation hawks. But he says, if job growth numbers remain depressed, the Fed could launch QE3 at its next meeting.